X now does Y 🙂

— Mythic Beasts (@Mythic_Beasts) 19 March 2019

Sensible people don’t like to hard code IP addresses in lots of different places in DNS. Better to assign it a name, and then reference that name, as it makes it clearer what’s what and if you ever need to change that IP, you’ve only got to do it one place.

CNAME records can be a good way to do this, by aliasing a DNS name to an IP. Unfortunately, the DNS specs prevent you using CNAMEs in various places that you might want to, most commonly at the root-level of your domain (the dreaded “CNAME and other data” problem).

This is where ANAME pseudo-records come in. They look just like a CNAME record, but rather than being added to the DNS, our server converts them into A and AAAA records. This allows you to get the benefits of a CNAME in places where a CNAME is not legal.

This week a customer suggested another use for ANAME records that we’d not previously thought of: round robin DNS. That is, a single DNS name that points to multiple servers. As you can’t have multiple CNAME records for the same hostname, implementing round-robin DNS means hard-coding A and AAAA records into your zone file. Like this:

proxy.mythic-beasts.com. 3600	IN	A	93.93.129.174
proxy.mythic-beasts.com. 3600	IN	A	46.235.225.189
proxy.mythic-beasts.com. 3600	IN	AAAA	2a00:1098:0:80:1000:3b:1:1
proxy.mythic-beasts.com. 3600	IN	AAAA	2a00:1098:0:82:1000:3b:1:1

Which is messy. Wouldn’t it be nicer to use the names of the servers involved? Like this:

proxy.mythic-beasts.com. 3600	IN	CNAME	 rproxy46-sov-a.mythic-beasts.com.
proxy.mythic-beasts.com. 3600	IN	CNAME    rproxy46-hex-a.mythic-beasts.com.

Sadly, the spec says you can’t do that, but thanks to a minor tweak to our DNS control panel code, you can now do it with ANAME records. Simply specify multiple ANAME records for your host name, and we’ll go and find all A and AAAA records for all of the hosts that are referenced.

Thanks to @grayvsearth for the suggestion on this one.

ANAME records are available in our DNS management interface, which is included with all domain registrations, and available for free on other domains for customers of other services. Other features include a DNS API, allowing you to obtain Wildcard Let’s Encrypt certificates.

Wildcard… sounds a bit like wildcat… cat pics!
Photo by Peter Trimming, CC BY 2.0

We’ve just made some changes to our plugin for dehydrated in order to better support Let’s Encrypt wildcard certificates.

Unlike normal certificates, which can be obtained using a web-based challenge, Let’s Encrypt’s wildcard certificates require a DNS-based challenge. In other words, you need to prove that you can control the DNS for the domain for which you are requesting a wildcard certificate.

Mythic Beasts provides a simple API for controlling DNS, which makes it possible to automate the process of responding to these challenges, and we provide a plugin for the popular dehydrated client that does just this.

We’ve just deployed a minor change which means that it’s now possible to obtain a single certificate for a domain, and a wildcard under that domain.

Access to our DNS API is included with all domain registrations. For more information, please see our instructions on using DNS-based challenges wih Let’s Encrypt. Please note that in order to obtain wildcard certificates you need to be using dehydrated version 0.6.0 or later.

A Mythic Beast eating a Retrosnub (artists impression)

Just before Christmas we were approached by Malcolm Scott, director of Retrosnub, a small cloud hosting provider in Cambridge. His existing connectivity provider had run out of IPv4 addresses. They’d decided to deal with this issue by adding charges of £2 per IPv4 address per month to encourage existing customers to return unused IPv4 addresses to them. As a cloud hosting provider with a substantial number of virtual machines (VMs) on a small number of hosts this had the result of tripling the monthly colocation bill of Retrosnub.

Aware of my presentation on IPv6-only hosting at UKNOF, Malcolm knew that opportunities for significant expansion were severely limited due to the difficulty of obtaining large amounts of IPv4 address space. Retrosnub faced a future of bankruptcy or remaining a very niche provider. His connectivity providers seemed strongly in favour of Retrosnub going bust so they could reclaim and re-sell the IPv4 space for higher margin services.

There are no expansion opportunities for new cloud hosting providers.

As a larger provider with our own address space, we had sufficient spare capacity in our virtual machine cloud to absorb the entire customer base of Retrosnub with no additional expenditure. Our work in supporting IPv6-only virtual machines will also make it easier to significantly reduce the number of IPv4 addresses required to support Retrosnub services. We formed a deal and agreed to buy the customer base of Retrosnub.

Combining operations

Since agreeing the deal, we’ve been working hard to merge our operations with minimum disruption.

The top priority was the domain name services because domains expire if you don’t renew them. Doing a bulk transfer of domain names between registrars is something which Nominet, the body responsible for UK domains, makes extremely easy, as it just requires changing the “tag” on all the domains.

Unfortunately, just about all other TLDs follow a standard ICANN process, which requires that a domain be renewed for a year at the time of transfer, and that the owner of the domain approves the process. If you were designing a process to destroy competition in a market by making it hard for resellers to move between registrars, it would look quite like this.

We’ve now got the bulk of domains transferred, and the next steps will be to migrate the DNS records from Retrosnub to Mythic Beasts so that our control panel can be used to change the records.

At the same time, we rapidly formulated a plan to migrate all the virtual machines in to stem the financial losses. Moving the VMs required an unavoidable change in IP address, and we also wanted to get them migrated from their current platform (Citrix Xenserver with para-virtualisation) to our own platform (KVM with full hardware virtualisation).

In order to ease the transition, we arranged for a pair of servers to do IP forwarding: a server in our cloud that forwarded the new IP to the VM in the Retrosnub cloud until it was migrated in, and another in the Retrosnub cloud that forwarded the old IP after the server had been moved. By doing this we were able to give customers a one week window in which to complete their IP migration, rather than forcing it to be done at the time that we actually moved the VM.

In the process of this migration, all customers received a significant bandwidth upgrade and majority received disk, RAM and CPU upgrades too.

We completed this on schedule before the quarterly colocation bill arrived, so instead of paying the much increased bill, we cancelled the contract and removed the servers from the facility.

Next steps

Our next step will be to migrate all the web and email hosting customers into our standard shared hosting environment. This has some time pressure as Google have plans for Chrome to start marking all non-HTTPS websites as insecure. We offer one click HTTPS hosting using Let’s Encrypt on all of our hosting accounts.

Fortunately we don’t buy domains in Bitcoin

Most of our domains are billed to us in US Dollars, so our pricing is at the mercy of the GBP/USD exchange rate.  The pound has strengthened significantly against the dollar since we last reviewed our pricing, so we’ve just rolled out reductions on many of our domain registration prices.  For example, .com domains drop by £2 to £11 + VAT, and .cymru (which, confusingly, we buy in dollars) drops by £3.50 to £22.

We aim to offer straightforward, no-nonsense pricing with no unsustainable introductory discounts that punish customer loyalty with inflated prices in subsequent years.  We price our domains at a level that allows us to properly support our customers.

A handful of the hundreds of different organisations, all of whom must be trustworthy.

Everybody knows that SSL is a good idea. It secures communications. At the heart of SSL is a list of certificate authorities. These are organisations that the confirm the identity of the SSL certificate. For example, if GeoTrust says that Raspberry Pi is Raspberry Pi we know that we’re talking to the right site and our communications aren’t being sniffed.

However, the list of certificate authorities is large and growing and as it stands, you’ve got to trust all of them to only issue certificates to the right people. Of course, through incompetence or malice, they can make mistakes.

CAA records are a relatively new mechanism that aims to stop this happening, making it harder to impersonate secure organisations, execute bank robberies and steal peoples’ identities.

CAA records enable you to list in your domain’s DNS the certificate authorities that are allowed to issue certificates for your domain. So, Google has a record stating that only Google and Symantec are allowed to issue certificates for google.com. If someone manages to persuade Comodo they are Google and should be issued a google.com certificate, Comodo will be obliged to reject the request based on the CAA records.

Of course, in order to be of any use, you need to be able to trust the DNS records. Fortunately, these days we have DNSSEC (dns security).

How does it work?

A typical CAA record looks something like this:

example.com. IN CAA 3600 0 issue "letsencrypt.org"

This states that only Let’s Encrypt may issue certificates for example.com or its subdomains, such as www.example.com.

Going through each part in turn:

• example.com – the name of the hostname to which the record apply. In our DNS interface, you can use a hostname of “@” to refer to your domain.
• IN CAA – the record type.
• 3600 – the “time to live” (TTL). The amount of time, in seconds, for which this record may be cached.
• 0 – any CAA flags
• issue– the type of property defined by this record (see below)
• "letsencrypt.org" – the value of the property

At present, there are three defined property types:

• issue – specifies which authorities may issue certificates of any type for this hostname
• issuewild – specifies which authorities may issue wildcard certificates for this hostname
• iodef – provides a URL for authorities to contact in the event of an attempt to issue an unauthorised certificate

CAA records can be added using the new section at the bottom of the DNS management page in our control panel:

The @ in the first field denotes a record that applies to the domain itself.

At Mythic Beasts, we’re a bit skeptical about the value of CAA records. In order to protect against the incompetence of CAs, they rely on CAs competently checking the CAA records before issuing certificates. That said, they do provide a straightforward check that CAs can build into their automated processes to detect and reject unauthorised requests, so publishing CAA records will raise the bar somewhat for anyone looking to fraudulently obtain a certificate for your domain.

Company policy requires that all blog posts have a picture.

We’ve just added support to our control panel and DNS API for “ANAME” records. ANAME records, also known as ALIAS records, aren’t real DNS records, but are a handy way of simulating CNAME records in places where you can’t use a real CNAME.

It works like this:

You’ve got DNS for your domain managed with Mythic Beasts, and you want to host your website with some 3rd party service provider. They’ll tell you to point DNS for your website at their server. You create a CNAME record for www.yourdomain.com and point it at server.3rdparty.com. So far so good.

You also want requests for your bare domain, e.g. http://yourdomain.com to be served by your provider, so you try to create a CNAME for yourdomain.com and get told you can’t. This is because you will already have MX, NS and SOA records for your bare domain, and CNAMEs aren’t allowed to co-exist with other records for the same name.

The usual fall back is to create A or AAAA records that point directly to the IP address of server.3rdparty.com, but this sucks because their IP is now hard coded into your zone, and if they ever want to change the IP of that server they’ve got to try and get all of their customers to update their DNS.

The nice solution would be SRV records, standardised DNS records that allow you to point different protocols at different servers. Unfortunately, they’re not supported for HTTP or HTTPS.

This is where ANAME records come in. You can create an ANAME just like a CNAME, but without the restrictions on co-existing with other records. We resolve the ANAME and substitute the corresponding IP addresses into records into your zone. We then regularly check for any changes, and update your changes accordingly.

Naturally, our ANAME implementation fully supports IPv6: if the hostname you point the ANAME at returns AAAA records, we’ll include those in addition to any A records returned.

Over the past twelve months we’ve implemented Domain Name Security Extensions, initially by allowing the necessary records to be set with the domain registries, and then in the form of a managed service which sets the records, signs the zone files, and takes care of regular key rotation

Our beta program has been very successful, lots of domains now have DNSSEC and we’ve seen very few issues. We thought that we should do some wider testing with a larger number of users than our own website, so we asked some friends of ours with a busy website if they felt brave enough to give it a go

Eben Upton> I think this would be worth doing.
Ben Nuttall> I'll go ahead and click the green button for each domain.
-- time passes --
Ben Nuttall> Done - for all that use HTTPS.

So now we have this lovely graph that indicates we’ve secured DNS all the way down the chain for every request. Mail servers know for definite they have the correct address to deliver mail to, Web requests know they’re at the correct webserver.

The only remaining task is to remove the beta label in our control panel.

Raspberry Pi DNSSEC visualisation, click for interactive version

It’s been a long time coming, but we’re now pleased to announce that we’ve got DNSSEC support in public beta, and you can enable it for your domain at the click of a button.

What is DNSSEC?

DNSSEC is a set of extensions to the DNS protocol that ensures that you can trust the IP addresses that you get back from the DNS system. For example, if you visit www.yourbank.com, the first thing that happens is that your browser uses a DNS server to find out the IP address of your bank’s web server. But how do you know that you can trust the address that you get back? Your request will probably get bounced through multiple DNS servers, such as your home router, your ISPs servers, and finally the authoritative server for the domain. If any one of those gets compromised (and let’s face it, home routers have a terrible security record) it could easily insert a different IP address and direct your request to an entirely different server.

DNSSEC means that all responses are signed with encryption keys that have been lodged with the registry, so you can’t inject bogus responses just by compromising an intermediate server.  Of course, the system only works if the systems making the requests check the signatures of the responses that they receive, something which certainly doesn’t happen everywhere yet.

Sounds complicated?

Yes it is, particularly as it is recommended that the encryption keys that you use are changed (or “rotated”) regularly. Fortunately, we’ve now automated all the hard stuff, and if you’ve got your domain registration and DNS hosting with Mythic Beasts, you can make DNSSEC go just by hitting a big green button.  We’ll take care of the rest:

Unlike some people, we believe that the internet should be a safe place to do business by default, so this service is, and will continue to be, provided at no extra cost.

If you want to try it out, simply visit our control panel, find the domain under “My Domains” and follow the “DNSSEC” link.

You could save as much as this by renewing early

On 1st March, Nominet (the UK domain registry) are raising their wholesale prices by 50% for all registration periods except 1 year registrations (which are rising by less, but are currently disproportionately expensive), and we will be applying corresponding increases to our prices for these domains.

If your domain is due for renewal in the next six months, you can save a few quid by renewing early.  You can renew your domain in advance for up to nine years.

Our new and old prices are as follows:

Nominet are celebrating 30 years of .uk with a buy one, get one free offer on .uk domains. The offer applies to one and two year registrations of new .uk, .co.uk, .org.uk and .me.uk domains bought within a 7 day period.

If you’d like to take advantage of the offer, simply register the first domain through our website in the normal way, and then email us with the name of the second domain you’d like to register.

We’ve also got promotions available on lots of other domains. The discounts offered vary quite a lot by registry, particularly when it comes to multi-year bundles. Some of the best discounts are available for .beer, .host and .site.

Please see our Domains Page for the full list of current discounts.